Cartridge fuse pull-out switch



1966 M. J. GEORGE ETAL 3, 84,598

' CARTRIDGE FUSE PULL-OUT SWITCH Filed Jan. 6, 1965 5 Sheets-Sheet 1 |1l UM 55c Z6 iVeZwm JGeor e ii, l J 9 ,i/a 7 1 1617? (522272 ac/ 54a 3k 70W2 4. M

8, 1956 M. .1. GEORGE ETAL 3, 84,598

CARTRIDGE FUSE PULL-OUT SWITCH Filed Jan. 6, 1965 3 Sheets-Sheet 5m 563% 56a, 355 385 flc Nov. 8, 39% J. GEORGE ETAL 3,284,598

CARTRiDGE FUSE PULL-OUT SWITCH Filed Jan. 6, 1965 5 Sheets-Sheet 3United States Patent l 3,284,598 CARTRIDGE FUSE PULL-OUT SWITCH MelvinJ. George, Ferndale, Mich, and Harris I. Stanback, Lexington, Ky.,assignors to Square D Company, Park Ridge, Ill., a corporation ofMichigan Filed Jan. 6, 1965, Ser. No. 423,680 8 Claims. (Cl. 200133)This invention relates generally to cartridge fuse pullout switches, andmore particularly to a cartridge fuse pu'l-l-out switch adapted to beplugged into an electrical panelboard.

An object of the invention is to provide a cartridge fuse pull-outswitch including a casing and an elongated fuse holder removablyinsertable therein axially of a cartridge fuse held by the fuse holder,the fuse holder including a pair of generally flat contact bladesdisposed at right angles to each other on adjacent longitudinal sides toperm-it over-lapping of the contact blades axially of the fuse and thusprovide :sufiicient resiliency in the contact blades on fuse holders forshort fuses.

Another object is to provide a fuse holder for such a cartridge fusepull-out switch, the fuse holder having a body formed of electricallyinsulating material and including an integral port-ion preventingcontact between a fuse clip secured to the fuse holder and a terminalstrap in the casing when the switch is electrically energized and thefuse holder is inserted in the casing by a workman while he isinadvertently touching the fuse.

A further object is to provide a fuse holder for such a cartridge fusepull-out switch, the fuse holder including a body portion formed ofelectrically insulating material and a bracket member secured to thebody portion and carrying a separate insulating member for preventingcontact between a fuse clip secured to the body portion and a terminalstrap in the casing when the switch is electrically energized and thefuse holder is inserted in the casing by a workman while he isinadvertently touching the fuse.

Still another object is to provide a fuse holder for such a cartridgefuse pull-out switch, the fuse holder having a body formed ofelectrically insulating material and including an otherwise solid sidewall portion having a slot therethr-ough for accommodating a tool forprying a fuse out of a pair of fuse clips secured to the body.

Other objects will appear when the following specification is consideredalong with the accompanying drawings in which:

FIG. 1 is a side elevational view of a cartridge fuse pullout switchconstructed in accordance with the invention;

FIG. 2 is an end elevational view of the switch of FIG. 1;

FIG. 3 is a top view of the switch of FIG. 1;

FIG. 4 is an enlarged sectional view of the switch of FIG. 1 takengenerally along the line 4-4 of FIG. 8;

FIG. 5 is a perspective view of one of the fuse holders of the switch ofFIG. 1;

FIG. 6 is a perspective view of the line terminal strap and plug-in lineterminal assembly of the switch of FIG. 1;

FIG. 7 is an enlarged sectional view of the switch of FIG. 1 takengenerally along the line 7-7 of FIG. 8;

FIG. 8 is an enlarged view of the switch of FIG. 1, with half of thecasing removed and with the fuse holders shown in section;

FIG. 9 is an enlarged sectional view of the switch FIG. 1 takengenerally along the line 99 of FIG. 8;

FIG. 10 is a view of the fuse holder shown in FIG. 9 taken from the leftof the fuse holder as shown in FIG. 9 and omitting the casing;

FIG. 11 is a view of the 'fuse holder taken from the left of FIG. 10;

FIG. 12 is a fragmentary view similar to the fuse holder 3,284,598Fatented Nov. 8, 1966 of the switch of FIG. 1 as shown in FIG. 9, butshowing a modified fuse holder;

FIG. 13 is a fragmentary view of the modified fuse holder taken from theleft of FIG. 12;

FIG. 14 is a perspective view of a portion of the modiiied fuse holderof FIGS. 12 and 13; and

FIG. 15 is a fragmentary view of a dual fuse holder usable in a doubleswitch unit such as would be formed by securing two switches like theswitch of FIG. 1 together.

FIGS. l3 show a cartridge fuse pu l-out switch 20 constructed inaccordance with the invention and includ ing a casing 22 and a pair offuse holders 24 removably insertable therein selectively in ON and OFFpositions.

' e casing 22 is molded of electrically insulating material and includestwo generally symmetrical halves 22a and 22b held together preferably bya plurality of rivets 23 and provided with appropriate internalprojections and pockets for securing various parts of the switch inproper position and for removably receiving the fuse holders 24.

FIG. 8 shows an enlarged view of the switch 20 with the casing half 22aremoved. Various parts of the switch trapped between the casing halves22a and 22b include a line terminal strap and plug-in line terminalassembly 26 (best shown in FIG. 6), a pair of lamps 28 for indicatingblown fuses, a pair of generally U-shaped spring members 30 electricallyconnected respectively to the indicating lamps 28, each spring member 30having a pair of leg portions disposed on opposite sides of theassociated indicating lamp 28 and a bight portion from which a yieldablestationary contact portion 32 depends, a pair of resistors 34electrically connected respectively to the indicating lamps 28, a pairof load terminal straps 37 and 38, and a pair of spring members 40eooperable respectively with the load terminal straps 37 and 38 toprovide load terminals. Also trapped between the casing halves 22a and22b and around one of the rivets 23 is a mounting clip 42.

The terminal assembly 26 (FIG. 6) includes a line minal strap portion26a which might be described as generally L-shaped with a long legportion 26b fiatwise offset in one direction and a short leg portion 260flatwise offset in an opposite direction. The leg portion 26b isprovided with raised stationary contact portions 26d and 26a forcooperation respectively with the fuse holders 24, as hereinafterdescribed, and with a bent tang portion 26 which aids in anchoring theassembly 26 in the casing 22. A pair of spring jaws 26g and 26h areriveted or otherwise secured to the leg portion 260 to provide a plug-intype line terminal.

Each of the indicating lamps 28 is provided with a lead wire 44electrically connected in any suitable manner to the associated springmember 30 and with a lead wire 46 electrically connected through therespective resistor 34 to the respective one of the load terminal straps37 and 38. Inner end portions 37a and 38a of the load terminal strapsform stationary contacts for cooperation respectively with the fuseholders 44, as hereinafter set forth. Outer end portions 371) and 38b'ofthe load terminal straps are grooved respectively at 37c and 380 (FIG.4) to receive a pair of load wires (not shown) insertable respectivelythrough a pair of openings 39 provided in the casing 22. The springmembers 40 cooperate respectively with the outer end portions 37b and38b to form load terminals, in a manner more fully set forth in US.Patent No. 3,133,999.

The fuse holders 24 are constructed as shown in full view in FIGS. 5, 9,10, and 11 and in section in FIGS. 4, 7, and 8. Each fuse holder 24includes a body 52 molded of electrically insulating material andprovided with an integral handle portion 52a, an inner combination fuseclip and movable contact blade member 54 secured to a wall terof thebody 52 as by a rivet 55, and an outer combination fuse clip and movablecontact blade member 56 secured to the same wall of the body 52 as by arivet 57. Each member 54 includes a generally U-shaped fuse clip portion540 as best shown in FIG. 4, and each member 56 includes a generallyU-shaped fuse clip portion 56a as best shown in FIG. 7, the fuse clipportions 54a and 56a of each fuse holder 24 being adapted to holdopposite end portions of a cartridge fuse 60 as best shown in FIG. 8.

Each member 54 includes a generally flat movable contact blade portion54b extending from the bight portion of the generally U-shaped fuse clipportion 54a and engageable with one of the stationary contact portions37a and 38a, as best shown in FIG. 8. Each member 56 includes agenerally flat movable contact blade portion 56b extending from one ofthe leg portions of the generally U- shaped fuse clip portion 56a andengageable with one of the stationary contact portions 26d and 26a, asbest shown in FIG. 9. Because each blade portion 54b extends from thebight portion of the respective fuse clip portion 54a while each bladeportion 56b extends from one of the leg portions of the respective fuseclip portion 56a, the blade portions 54b and 56b of each fuse holder 24are generally at right angles to each other. Each blade portion 56b thusmay be made to overlap a tongue portion 540 of the respective member 54in the axial direction of a respective fuse 60. This overlapping effectenables the blade portions 54b and 56b to be made longer, for greaterresiliency, than they could be if they were on the same side of therespective fuse holder. The rivet 55 of each fuse holder. extendsthrough the tongue portion 540 of the respective member 54, the tongueportion 540 in each instance extending from the bight portion of thefuse clip portion 54a oppositely from the respective blade portion 54b.

As shown best in FIG. 9, the body 52 of each fuse holder 24 includes aninner end portion 52b which extends laterally outward (toward the leftas viewed in FIG. 9) farther than the fuse clip portion 54a and thusprevents the fuse clip portion 54a from contacting the respectivestationary contact portion 260. or 26c as the fuse holder is insertedinto the casing 22. Therefore, if a workman inserts a fuse holder 24 inthe casing 22 while the stationary contact portions 26d and 26a are atline voltage and while he is inadvertently touching the respectivemember 56 or the outer end of the respective fuse 60, he will beprotected.

As will be understood, a double unit may be produced by securing'twocasings 22 together with longer rivets 23, and dual fuse holders 24a maybe produced by molding two bodies 52 connected by a common handleportion 52s but spaced apart exclusively of the common handle portionsufficiently to accommodate adjacent wall portions of two connectedcasings 22, as indicated at 61 in FIG. 15. On such a dual fuse holder,one of the fuses 60 can be pried out of its respective fuse clipportions 54a and 56a by prying between the fuse clip portions 54a and56a, as at 522 in FIG. 15, and the other of the fuses 60 can be priedout of its respective fuse clip portions 54a and 56a by prying through aslot 52d provided in the respective body 52. The location 52c and slot52d are shown more clearly in the single fuse holder 24 shown in FIG. 5,although the slot 52d is not necessary for a single fuse holder.

FIGS. l2, l3, and 14 show a modified fuse holder 24b which differs fromthe fuse holder 24 at the inner end portion. A molded body 62 of thefuse holder 24b is shorter than the body 52. of the fuse holder 24 andinstead of an integral protective.portion such as portion 52b of thefuse holder 24, the fuse holder 24b is provided with a separateprotective member 63 formed of insulating material and adapted toprevent contact between a fuse clip portion 64a of a combination fuseclip and movable contact blade member 64 and the respective stationarycontact portion 26d or 26c as the fuse holder 24b is inserted into acasing 22. The member 64 includes a movable contact blade portion 64bsimilar to the movable contact blade portion 54b of the member 54 of thefuse holder 24, and a tongue portion 640 similar to the tongue portion54c of the member 54. The member 64 is secured to the body 62 by a rivet65 extending through the tongue portion 640. The rivet 65 also secures alonger leg portion 68a of a generally L-shaped bracket 68 to the body62. The protective member 63 is secured to a shorter leg portion 68b ofthe bracket 68 by means of a rivet 69. Preferably the leg portion 68b isprovided with a circular dished configuration as at 680 in order thatthe inner head of the rivet 69 may be recessed within the member 63. Theleg portion 68a is provided with a humped portion 68d for receiving acenter portion of a wire spring member 70 between the humped portion andthe tongue portion 640 of the member 64. The opposite end portions ofthe spring member 70 embrace opposite legs of the fuse clip portion 64a,as best shown in FIG. 14, to impart added resilience thereto.

Various modifications may be made in the structure disclosed withoutdeparting from the spirit and scope of the invention as set forth in theappended claims.

We claim:

1. A cartridge fuse pull-out switch comprising a casing, a line terminalmounted adjacent one end of said casing, a terminal strap in said casingelectrically connected to said line terminal, and a pair of separateelongated fuse holders disposed in said casing, each of said fuseholders being re-movably insertable in the casing longitudinally of thefuse holder and axially of a cartridge fuse when a cartridge fuse ismounted in the fuse holder, each of said fuse holders being removablyinsertable in the casing selectively in ON and OFF positions, and eachof said fuse holders including a pair of generally fiat contact bladeslinearly displaced from each other along a longitudinal axis of the fuseholder and angularly displaced substantially ninety degrees from eachother about the longitudinal axis of the fuse holder, and said terminalstrap being engaged with a contact blade of each of said fuse holderswhen said fuse holders are in the ON position in said casing.

2. A cartridge fuse pull-out switch comprising a casing, a line terminalmounted adjacent one end of said casing, a terminal strap in said casingelectrically connected tosaid line terminal, and an elongated fuseholder disposed in said casing, said fuse holder being rem-ovablyinsertable in said casing longitudinally of the fuse holder and axiallyof a cartridge fuse when a cartridge fuse is mounted in said fuseholder, said fuse holder including an elongated body formed ofelectrically insulating material and a pair of inner and outer fuseclips mounted thereon, said body including an integral portion disposedinwardly of said inner fuse clip and extending beyond said inner fuseclip in a direction perpendicular to a longitudinal axis of said body toprevent contact between said inner fuse clip and said terminal strap assaid fuse holder is inserted into said casing.

3. A cartridge fuse pull-out switch comprising a casing, a line terminalmounted adjacent one end of said casing, a terminal strap in said casingelectrically connected to said line terminal and an elongated fuseholder disposed in said casing, said fuse holder being removablyinsertable in said casing longitudinally of the fuse holder and axiallyof a cartridge fuse when a cartridge fuse is mounted in said fuseholder, said fuse holder including an elongated body formed ofelectrically insulating material and a pair of inner and outer fuseclips mounted thereon, a bracket secured to said body and having aportion disposed inwardly of said inner fuse clip, and an insulatingmember secured to said bracket portion inwardly of said inner fuse clipand extending beyond said inner fuse clip in a direction perpendicularto a longitudinal axis of said body to prevent contactbetween said innerfuse clip and said,

terminal strap as said fuse holder is inserted into said casing.

4. A dual fuse holder for a cartridge fuse pull-out switch, said fuseholder comprising a pair of elongated spaced apart body portions formedof electrically insulating material and joined solely adjacent one endby a common handle portion, each of said body portions having a pair ofleg portions defining a generally L-shaped cross section correspondinglydisposed tothe generally L- shaped cross section of the other bodyportion, each of said body portions having a pair of fuse clips mountedon one of its leg portions for receiving a cartridge fuse in a directiongenerally parallel to the other of its leg portions, and the one bodyportion having its said other leg portion disposed remotely from theother body portion having a slot through its said other leg portion toaid in removal of a cartridge fuse from the fuse clips of said one bodyportion.

5. A cartridge fuse pull-out switch as claimed in claim 1, wherein thecontact blades of each of said fuse holders overlap each otherlongitudinally of the fuse holder.

6. A cartridge fuse pull-out switch as claimed in claim 3, including aspring member having a mounting portion held between said inner fuseclip and said bracket and having portions urging the legs of said innerfuse clip toward each other to increase the clamping pressure on an endportion of a fuse mounted therein.

7. A fuse holder for a cartridge fuse pull-out switch, said fuse holdercomprising (a) an elongated body formed of electrically insulatingmaterial and including a mounting wall portion,

(b) a first electrically conductive combination fuse clip and contactblade member mounted on said mount ing wall portion and including (1) agenerally U-shaped fuse clip having (a) a bight portion disposed on aninner side of said mounting wall portion and extending generallyparallel to said mounting wall portion, and (b) a pair of spaced legportions extending from said bight portion inwardly and away from saidmounting wall portion and adapted to clampingly receive an end portionof a cartridge fuse therebetween, and

(2) a generally flat contact blade extending from one of said legportions of the fuse clip of said first member generally longitudinallyof said body in generally perpendicular relationship to said mountingwall portion, and

(c) a second electrically conductive combination fuse clip and contactblade member mounted on said mounting wall portion in spacedrelationship to said first member longitudinally of said body andincludmg (1) a generally U-shaped fuse clip having (a) a bight portiondisposed on an outer side of said mounting wall portion and extendinggenerally parallel to said mounting wall portion, and

(b) a pair of spaced leg portions extending from said bight portioninwardly past said mounting wall portion and adapted to clampinglyreceive the other end portion of a cartridge fuse therebetween, and

(2) a generally flat contact blade extending from the bight portion ofthe fuse clip of said second member generally longitudinally of saidbody in generally parallel relationship to said mounting Wall portion.

8. A fuse holder as claimed in claim 7, wherein said second memberincludes a generally flat mounting tongue extending from the bightportion of the fuse clip of said second member oppositely from saidcontact blade of said second member, and said mounting tongue extendslongitudinally of said body into partially overlapping relationship withsaid contact blade of said first member on the opposite side of saidmounting wall portion.

References Cited by the Examiner UNITED STATES PATENTS 1,966,716 7/1934Green 200-114 2,581,308 1/1952 Smith 200-133 X 2,621,227 12/1952 McMahon339-258 X 2,984,723 5/1961 Jacobs 200-113 BERNARD A. GILHEANY, PrimaryExaminer. H. B. GILSON, Assistant Examiner.

1. A CARTRIDGE FUSE PULL-OUT SWITCH COMPRISING A CASING, A LINE TERMINAL MOUNTED ADJACENT ONE END OF SAID CASING, A TERMINAL STRAP IN SAID CASING ELECTRICALLY CONNECTED TO SAID LINE TERMINAL, AND A PAIR OF SEPARATE ELONGATED FUSE HOLDERS DISPOSED IN SAID CASING, EACH OF SAID FUSE HOLDERS BEING REMOVABLY INSERTABLE IN THE CASING LONGITUDINALLY OF THE FUSE HOLDER AND AXIALLY OF A CARTRIDGE FUSE WHEN A CARTRIDGE FUSE IS MOUNTED IN THE FUSE HOLDER, EACH OF SAID FUSE HOLDERS BEING REMOVABLY INSERTABLE IN THE CASING SELECTIVELY IN ON AND OFF POSITIONS, AND EACH OF SAID FUSE HOLDERS INCLUDING A PAIR OF GENERALLY FLAT CONTACT BLADES LINEARLY DISPLACED FROM EACH OTHER ALONG A LONGITUDINAL AXIS OF THE FUSE HOLDER AND ANGULARLY DISPLACED SUBSTANTIALLY NINETY DEGREES FROM EACH OTHER ABOUT THE LONGITUDINAL AXIS OF THE FUSE HOLDER, AND SAID TERMINAL STRAP BEING ENGAGED WITH A CONTACT BLADE OF EACH OF SAID FUSE HOLDERS WHEN SAID FUSE HOLDERS ARE IN THE ON POSITION IN SAID CASING. 